Adjustable gantry



July 4, 1961 Filed April 4, 1958 B. E. WALLACE ADJUSTABLE GANTRY 2 Sheets-Sheet 1 INVENTOR ATTORNEYS July 4., V1961 B. E. WALLACE 2,990,788

ADJUSTABLE GANTRY Filed April 4, 1958 2 Sheets-Sheet 2 INVENTOR WXM ATTORNEYS States Patent 2,990,788 ADJUSTABLE 'GANTRY Bernard E. Wallace, Box 163, Exton, Pa.

Filed Apr. 4, 1958, SeniNo. 726,560 3 Claims. (Cl. 104-126) `This invention relates to gantries and is particularly concerned with the provision of an improved construction by means of which certain adjustments can be made whereby to greatly increase the usefulness and mobility of these devices.

As is well known to those skilled in the art a gantry consists primarily of what may be ter-med a bridge member having at either end some suitable supporting structure upon which it can be moved from place to place. These suports can take various forms which may be referred to as towers, legs or the like depending upon their size and structural makeup. The present invention is especially applicable to gantries of relatively simple construction in which the end supports take lthe form of an A-frame, i.e`., a frame having two legs and an interconnecting cross member near the lower ends of thev legs.

` The principal objects of the invention are to provide a construction of the character described wherein the legs at either end of the gantry are capable of independent adjustment whereby one end of the ygantry can stand on a platform or truck bed or in a pit, thereby greatly increasing the number of places where the de-v vice can 'be employed; to provide a construction employing wheels or casters which are readily removable so that the gantry can be set up on rough terrain or other locations where each leg may have to be of a different.

length; to provide a gantry having supporting legs theA spread of which can be altered regardless of whether the casters are attached or removed thus making it possible to facilitate setups in different locations, topermit rolling the gantry down narrow aisles or the like and to give greater stability with resulting safety in relation to the load being handled; to provide a ygrantry construction which permits the overhead beam or bridging member to hang in a plumb position regardless of the slope upon which the end supports are resting; to provide gantry construction which is capable of various adjustments without setting up internal strains in the structural parts such as might beencountered on uneven floors or other terrain; to provide a gantry construction the legs of which are suitably braced by diagonal braces arranged so as not to interfere with the free movement of trolleys or other devices which may be operating along the bridging member; to provide a gantry construction embodying certain connections for the legs by means of which the gantry can be easily folded into a convenient position for hauling. or storage but without the lneed for total dismantlement; and to simplify and strengthen structures of this kind as well as to reduce manufacturing and maintainence costs.

`How the foregoing objects and advantages together with such others as may appear hereinafter or are incident to my invention are attained is illustrated in a preferred embodiment in theraccompanying drawings wherein:

FIGURE 1 is a side elevation with the central portion of the I-beam or bridging member broken out in order to shorten the length of the iigure;

FIGURE 2 is a plan view of FIGURE 1; A

FIGURE 3 is an end view looking toward the left inFIGUREl; l

FIGURE 4 is a fragmentary longitudinal section taken approximately as indicated by the line 4-4 on FIGURE 3 but with certain parts appearing in elevation; and

FIGURE 5 is a cross section taken as indicated by the line 5-5 on FIGURE 4.

Patented July 4, 1961 By referring to the drawings it will be seen that my improved gantry comprises preferably an -I-beam bridging member 6 having at each end a supporting struc-l ture indicated generally by the reference character A. These supporting structures are identical in the present embodiment although it might well be possible to employ a different type of support at one end say, for example, one that is fixed in dimension instead of adjustable, although in such a case the gantry would not be capable of as wide a range of functional usefulness as is characteristic of the preferred embodiment illustrated. I will now'describe the supporting structure at one end with the understanding that in the present embodiment the two ends are identical although reversed.

A longitudinally extending supporting bar 7 lies above each end of the bridging member 6 in substantially parallel relationship therewith and the bridging member is hung from these bars as by inverted U-bolts 8. Suitable cradles 9 are provided between the upper flanges of the I-beam and the under side of the supporting bars 7. rIhese cradles are llat on the bottom to rest firmly on the flanges 6a of the I-beam and are suitably concaved above and at the sides adjacent the legs of the U in order to properly tit against the under side of the bars 7 and the inner sides of the legs of the U. This is shown probablyA most clearly in. FIGURE 5 from which figure it will "also be seen that the legs of the U pass through suitable apertures in the flanges 6a of the I-beam and that'theI-beam is held in place by the nuts 8a.

' At .their outer ends the bars 7 extend a short distance beyond the d-beam 6 in order to provide a bearing point l 1 for the legs 10 upon which the .gantry rests and is supported. At the upper end of each leg there is provided a hinge member 11 formed to receive the end of the supporting bar 7. The hinges are properly positioned by sturdy cotter pins 12, one at each side of the pair of hinges 11.

Each hinge member consists of a yoke `11a adapted to4 embrace the upper end of the leg 10 and a pair of earsv 11b with one ear otset at a slightly greater distance from the center or axis of the leg 10 than the other as most clearly shown in FIGURES 2 and 4. The ears are spaced apart sufficiently far so Ithat they can be intermeshed also as shown in FIGURES 2 and 4. By this means I am enabled to substantially centralize the load supporting point in line with the axis of the legs which makes Vfor stability and strength land avoids setting up undue twisting or other stresses or strains in the structure as will further appear.

'Ihe upper end of the leg 10 tsinto the yoke 11a andV is pinned thereto by means of a bolt 13 the axis oct which is arranged at right angles to the axis of the bars 7 upon which the I-beam swings. This permits the leg to be swung outward longitudinally of the gantry or inward to assume a position along side of the web of the I-beam 6, this latter provision making it possible to collapse the gantry structure for shipping but without completely dismantling the device.

I Each leg 410 is made extensible by means of an innerl telescoping member 10a which latter `is provided with a series of apertures 10b into which a pin 10c is adapted. v'to project. The pin 10c cooperates with the reinforcingY collar 10d to hold the extensible member 10a in any desired position of adjustment with respect to the other" member 10 of the leg.

`Each collar 10d has a hub or projection 10e for receiving the apertured ear 14a in thev lower end of a diagonal brace member 14. The upper end of this diagonal brace member is curved to provide another ear 14b which ts over the reduced extension 7a of the supporting bar 7. On the outside a suitable cotter pin 1S may be employed to hold the ears in position on the extension 7a and at the lower end a cotter pin 16 is supplied to hold the ear 14a in position.` .Y

I should like to point out that the brace members 14 and their ears 14a and 14b are formed so that they'pro ject outwardly beyond the plane of the bridging I-beam 6 in order to avoid interfering with the trolley or other device which is adapted to move along the I-bearn in a manner well understood in the art.

The lower end of each extensible member 10a is provided with a reinforcing collar 17 towhich is pivotally attached a caster fitting 18 by means of a bolt 19 the axis of which latter is parallel with the axis of the supporting bar 7. These fittings 18 open upwardly in a substantial U-shape to .permit this mounting as appears most clearly in FIGURE 1. The caster fittings at each end of the gantry are connected by a frame member which, preferably, takes the form of Ia telescoping, two-part rod 20-20a, the inner member 20a being provided with a series of transverse apertures 2Gb adapted to cooperate with an aperture in the tubular member 20 and with the pin 21 so that the two parts of the extensible rod may be held in various positions of adjustment. The outer ends of the rod Z-20a are secured to the caster fittings in any desired manner as by pins 22.

The casters 23, of course, are swivelly mounted on the bottom of the caster fittings 18 in any desired manner familiar to those skilled in the art.

At this point I wish to emphasize the fact that all four of the hinge points for the legs and the bracing members at both ends of the I-beam must be on a substantially common axis of rotation above the I-beam. Otherfwise, the I-beam will not be free to swing into a plumb position laterally of the gantry especially in situations where the gantry is not set up on a level surface. Furthermore, the axis of caster rotation must always be substantially perpendicular both to the axis of the supporting bar 7 and the axis of the connecting rod 2li-20a. It should also be noted that it is necessary for the longitudinal axis of the legs at either end to lie in a common plane at all times or that they should generate a common cone if angularly displaced with respect to the axis of the bars 7 and rotated around said bars. Additionally, the plane must be perpendicular to the longitudinal axis of the bars 7 or if the legs lie in a cone, the axis of the bars must be common to the cone axis. In this way, the bolts 19 are at all times kept parallel to each other with respect to their longitudinal axis as well as parallel to the axis of the bars 7. If this were not so, the angular displacement between the bolts 19 would vary as the spread between the caster fittings 18 is altered. Finally, the bolts 19 must not be laterally displaced with respect to each other. All of these factors are important to the design in order to avoid setting up undue stresses and strains in the structure of the gantry. This also insures easy removal and insertion of the pins 10c and 21.

It will now be apparent that I have provided a gantry in which the legs can be individually adjusted to whatever height is Amost suitable for the terrain upon which the gantry is being operated. The legs may be lengthened or shortened and they may be spread apart to a greater or lesser degree within the limits of the construction. Furthermore, when desirable or necessary, the casters and the framing which interconnects them can b e readily removed so that each leg can be separately adjusted as to height and position as may be required on rough terrain. It 4will also be seen that the legs at one end can be set to stand on a platform, a truck bed or in a pit while the legs at the other end are adjusted to rest upon the floor. This greatly increases the usefulness of equipment of this kind. Another advantage flowing from my improved construction is that the gantry may be lowered to pass under obstructions when being moved from one location to another or its legs may be drawnrtogether so as to permit rolling down narrow aisles or the like or spread widely to provide stability and increased safety.

Another outstanding advantage arises by virtue of the fact that the I-beam or bridging member proper is always free to hang in a plumb position even though the end supports rest on a slope or are otherwise out of alignment due to the differences in conditions at the ends of the gantry. This feature is very useful because it eliminates setting up internal strains in the gantry structure such as might otherwise be encountered where the gantry is used on uneven floors or terrain. It should also be noted that by removing the casters and the framing interconnecting them and also the bracing members 14 it is possible to fold the legs into substantial parallelism with the bridging member which is a great convenience in moving or storing the gantry lwithout the need of completely dismantling the same.

I claim:

1. An end support for a gantry bridging member, said support comprising a horizontal bar above the bridging member, means for hanging the bridging member on the bar to swing in an arc around the bar as an axis, a pair o'f legs hinged on the bar also for swinging movement around the bar as an axis, said legs being adjustable as to length and said hinges being arranged so that the longitudinal axes of said legs will generate a common path as they swing around the bar axis, a fitting having a caster mounted on the lower end of each leg, and an adjustable rod connecting the caster 4fittings ywhereby to alter the spread between the legs, each of said caster fittingsbeing connected to its leg for swinging movement upon a pin the axis of which pin is parallel to the axis of the supporting bar above the bridging member and each caster being swivelly mounted in its fitting upon a vertical swivel axis whereby the spread between the legs and the length of the legs can be adjusted independently of each other while still maintaining the caster swivel axes in their vertical positions as described.

2. A gantry end support according to claim 1 wherein is provided a brace member for each leg, the upper end of -which is mounted for swinging movement around the bar as an axis.

3. A gantry end support according to claim 1 wherein the hinge mounting for the legs consists of a forked member for each leg, the axis of the leg being offset with respect to the fork, the legs being interchangeable and the forked members being intermeshed whereby the axes of the legs lie in substantially the same plane transversely of the bar axis.

References Cited in the le of this patent UNITED STATES PATENTS v1,362,141 Reisenberg Dec. 14, 1920 1,546,700 Allen July 21, 1925 2,342,015 Scheihing Feb. l5, 1944 2,449,501 Oertle Sept. 14, 1948 2,639,197 Chelsea May 19, 1953 FOREIGN PATENTS 678,661 Germany Ju1y'19, 1939 761,557 Germany `l'une 21, 1954 766,284 Great Britain Ian. 16, 1957 275,559 Switzerland Aug. 16, -1951 

